Currently Being ModeratedJul 9, 2013 1:22 PM (in response to PsychTech)
For one, Apple have never supported CPU upgrades for the XServes.
Secondly, the X5160 and X5570 use completely different socket models - in other words, they are not physically compatible. On that basis alone I'd say your chances were nil or less.
Currently Being ModeratedAug 8, 2013 8:11 PM (in response to PsychTech)
PsychTech not sure about that processor but I do know you CAN upgrade the processors in an XSERVE Late 2006. I upgraded mine from dual 2.0 Ghz to dual 3.0 Ghz I got them off ebay for seven bucks each. Here is a link to Apple's instructions for DIY processor upgrade: